Cardiac tests are used to diagnose and treat heart disease and peripheral vascular (vein and artery) diseases that can put you at risk for a stroke, heart attack, blood clot and loss of limbs. Non-invasive tests, like cardiac event monitors, stress tests, Holter monitors, echocardiograms (cardiac echo) and electrocardiograms (EKGs), are typically performed in an outpatient setting and provide your doctor with important information to make an accurate diagnosis.